MP2002 – LOW INPUT VOLTAGE, 500mA LINEAR REGULATOR
APPLICATION INFORMATION
Setting the Output Voltage
The MP2002 has an adjustable output voltage,
set via an external resistor divider (R1 and R2
in Figure 2).
⎛
V
−
V
FB
R1
=
R2
× ⎜
OUT
⎜
V
FB
⎝
⎞
⎟
⎟
⎠
Table 1—Adjustable Output Voltage R1 Values
(R2=10kΩ)
V
OUT
(V)
1.25
1.5
1.8
2
2.5
2.8
3
3.3
4
5
R1 (Ω)
15k
20k
26k
30k
40k
46k
50k
56k
70k
90k
where V
FB
= 0.5V (The OUT feedback threshold
voltage.)
Example: For 2.5V Output and R2=10kΩ
⎛
2.5
−
0.5
⎞
R1
=
10k
× ⎜
=
40k
Ω
0.5
⎟
⎝
⎠
A standard 40kΩ (±1%) resistor can be selected
for R1.
Table 1 lists the selected R1 values for some
typical output voltages (assuming R2 = 10kΩ).
Power Good
The power good pin is an open collector output
completed with a pull up resistor (10kΩ
recommended). The pull up resistor can be tied
to a supply within the voltage range of the pin
(0V to 5.5V). For example, the pull up resistor
can be tied to the input voltage when it is being
monitored by an IC powered from this input
voltage. It monitors the output voltage, and if
the output voltage is 10% below its regulation
point, the PG pin becomes low.
Bypass Capacitors
For lower noise, the reference voltage can be
bypassed by an external capacitor. A low ESR
capacitor, such as the ceramic type, will provide
the best performance.
MP2002 Rev. 1.11
10/10/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
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